Processes for breaking petroleum emulsions



June 26, 1951 M. DE GROOTE ET AL 2,558,510

PROCESSES FOR BREAKING PETROLEUM EMULSIONS Filed Nov. 1, 1949 MENTHYLCYCL OHEXANOL D C l-I 0 I00 I00? INVENTO s MELVIN 05 ROUTE ARTHUR F W/RTEL OWENPETT/NGILL A TTORNEY f'atented june :26,

UNITED STATES PATENT OFFICE PROCESSES FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, and Arthur F. Wirtel and Owen H. Pettingill, Kirkwood, Mo., assignors to Petrolite Corporation, Ltd., Wilmington, De1., a corporation of Delaware Application November 1, 1949, Serial No. 124,811

7 Claims. (c1. 252-s31) demulsification. See our co-pending application serial No. 124,812, filed November 1, 1949.

invention provides an economical and rapid processfor resolving petroleum emulsions of the water-in-oil type, that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion. 7 It also provides an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters 'or weak brines. Controlled emulsificatiori'and subsequent demulsification, under the conditions just mentioned, are of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

Demulsification, as contemplated in the present application, includes the preventive step of comingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion in the absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component.

. Briefly stated, the present process is concerned with the breaking of petroleum emulsions by means of certain glycol ,ethers of para-menthyl- 2 cyclohexanol, and particularly in the form of cogeneric mixtures, as hereinafter described. These products are obtained by treatment of paramenthylcyclohexanol with ethylene oxide and propylene oxide within the limits and manner hereinafter specified. a

It is well known that a variety of compounds containing'a reactive hydrogen atom, i. e., a

hydrogen atom attached to oxygen, nitrogen, or

sulphur, will react with alkylene oxides, partic ularly ethylene oxide, or propylene oxide, to yield the corresponding glycol or polyglycol derivative. Such oxyalkylated derivatives are readily prepared from chemical compounds in Which the hydrogen atom is directly attached to oxygen, and particularly in the case of alcohols or phenols, such as aliphatic alcohols, phenols, alkylaryl alcohols, alicyclic alcohols, phenoxyalkanols, substituted phenoxyalkanols, etc. Generally speaking, it has been found advantageous to react a water-insoluble hydroxylated material, having 8 carbon atoms or more, with an alkylene oxide so as to introduce water-solubility, or at least, significant or distinct hydrophile. character, with the result that the derivative so obtained has sur. face-active properties.

Examples of suitable reactants of this type include octyl alcohol, decyl alcohol, dodecyl alco hol, tetradecyl alcohol, octadecyl alcohol, butylphenol, propylphenol, propylcresol, hexylphenol, octylphenol, nonylphenol, and cardanol, as well as the corresponding alicyclic alcohols obtained by the hydrogenation of the aforementioned phenols. It has been suggested that at least some of such materials be used in the resolution of petroleum emulsions. As far as we are aware, none of such materials represent products which are acceptable in demulsification today from a competitive standpoint. In the majority of cases such products, are apt to be one-sixth, one-fifth, one-fourth, or one-third as good as available demulsifying agents on the same percentage-of-' active-material basis, or same cost basis.

We have discovered a very few exceptions to the above general situation. For example, We have discovered, if one treats para-menthylcyclohexanol with ethylene oxide and propylene oxide so as to yield a cogeneric mixture of glycol ethers, that such mixed derivative has unusual properties, provided that the composition lies within a certain range, as hereinafter specified. A specific exemplification of this range is the product obtained by treating one mole of para-menthylcyclohexanol with 23 moles of propylene oxide, and then with 27 moles of ethylene oxide. Similarly, one may treat the para-menthylcyclohexanol with the 2'7 moles of ethylene oxide first and then with the 23 moles of propylene oxide next.

In subsequent paragraphs from time to time reference is made to compounds or cogeneric mixtures. At first glance, it may appear that such language is indefinite, and perhaps, contradictory. It is the intention at the moment only to point out that there is no inconsistency in such description, and that, subsequently, there will be a complete explanation of why such desig nation is entirely proper.

The cogeneric mixtures of glycol ethers of para-menthylcyclhexanol are unusually effective demulsifying agents on a comparatively small number of oil field emulsions, which, 7 oddly enough, appear rather widely distributed geographically. These para-menthylcyclohexanol ether mixtures do not appear to be universally competitive, and, as a matter of fact, appear to be highly selective in regard to their action as demulsifying agents. However, such products have significant utility in a number of different oil fields where they serve better than any other available demulsifying agent. Their utility may, of course, increase as time goes along.

Para menthylcyclohexanol is obtained by the hydrogenation of menthylphenol. The procedure is essentially the same as employed in the conversion of phenol to cyclohexanol. The formula of menthylphenol is believed to be as follows:

lCH3

The product obtained by hydrogenation is, of course, the corresponding cyclohexanol, to wit, menthylcyclohexanol, the formula of which is as follows:

The moleciuar weight of para-menthylcyclohexanol is 232; the commercial product actually shows a molecular weight slightly more. For convenience, we have taken themole'cular weight of the commercial product -as 238.

It is very peculiar that the effectiveness of the demulsifying agents herein described seem to be limited to a very narrow range or area, as far as composition goes. The invention will be described by reference to the accompanying drawing, which illustrates, in conventional graphical form, compositions used in accordance with the invention in terms of the three components. The drawing is a conventional triangular graph showing compositions in terms of the three components. Thus, the drawing illustrates glycol ethers of para-menthylcyclohexanol, or cogeneric mixtures thereof, derivable from para-menthylcyclohexanol and ethylene oxide alone, or para-menthylcyclohexanol and propylene oxide alone, or para-menthylcyclohexanol and ethylene oxide, in terms of the initial reactants. We have found that effective demulsifying agents lie approximately within a small and hitherto unsuspected area indicated by the trapezoid determined by the points 8, 9, I0 and H. More specifically, particularly effective demulsif ying agents. appear within a smaller range, as set forth approximately by the area indicated by the segment of a circle in which the area of the segment is limited to derivatives in which menthylcyclohexanol contributes at least 4% by weight of the ultimate compound or cogeneric mixture.

The circle itself is identified by the fact that the points I, 3 and 6 appear on the circle. The more effective of these better compounds or cogeneric mixtures are those which appear within the triangle which represents part of the circle and part of the segment, to wit, the triangle identified by the points I, 3 and 6. The most effective compounds or cogeneric mixtures of all are those which fall within the inner central triangle of the larger outer triangle identified by the points I, 3 and .6, to wit, the smaller triangle identified by the points '2, 4 and 5. The most outstanding of these effective compounds or cogeneric mixtures is one which appears to fall substantially at the center of the smaller triangle identified by point I. This particular point is obtained by treating one mole of paramenthylcyclohexanol with 23.5 moles of propylene oxide, followed by treatment with 27.5 moles of ethylene oxide.

In spite of the unique character of the compounds previously described we have made additionally an invention within an invention. This can be illustrated by reference to the compounds or cogeneric mixtures whose composition is determined by the inner triangle 2, 4, 5. This preferred class of derivatives, or, for that matter, all the herein described products, can be made in three different ways: (a) by adding propylene oxide first and then ethylene oxide; (b') by-adding the ethylene oxide first and then propylene oxide; or (c) by adding the two oxides byra n dom, indifferent, or uncontrolled addition, so as to produce a polyglycol ether in which the pro- Pylene radicals or "ethylene radicals do not appear in continuous succession, but are heterogeneously distributed.

We have found that if propylene oxide is added first and then ethylene oxide is added, that the compounds so obtained are invariably and inevitably more effective 'as demulsifiers, and are also more efiective for other purposes than any other comparable glycol ethers of para-menthylcyclohexanol made by combining the three reactants in any other sequence. This will be larly, the most desirable ones, and also those s" which are helpful in setting the limits in the graph previously referred to, the following examples are included In connection with these examples, it will be noted that the oxyalkylation of para-menthylcyclohexanol, i. e-., by treatment lo with ethylene oxide or propylene oxide, or a mixture of the two, is conventional. The procedure is conducted in the same manner employed in connection with other alcohols, or the like, and

generally, an alkaline catalyst is employed. See, for example, U. S. Patent No. 2,440,093, dated April 20, 1948, to Israel,.and British Patent No. 602,591, applied for February 12, 1945. r

Example 1 2 The reaction vessel employed was astainless steel autoclave with the usual devices for heating, heat-control, stirrer, inlet, outlet, etc., which is conventional in this type of apparatus. The capacity was approximately 40 gallons. The stirrer operated at a speed of approximately 250 R. P. M. There were charged into the autoclave 23.8 pounds of para-menthylcyclohexanol. There were then added one pound 3 ounces (approximately 5% by weight) of ground caustic soda. The autoclave was sealed, swept with nitrogen gas, and stirring started immediately and heat applied, and the temperature allowed to rise to approximately 150 C. At this point addition of propylene oxide was started. It was added con"- tinuously at such speed that it was absorbed by the reaction asrapidly as added. The amount of propyleneoxide added was 136 pounds. The time required to add this propylene oxide was slightly in excess of one hour, about 1 hours. During this time the temperature was maintained at 150 to 160 C., using cooling water through the inner coils when necessary, and otherwise applying heat, if required. Atthe end of the addition of the propylene oxide there was added ethylene oxide, as previously-indicated; The amount of ethylene oxide added was 120.5 pounds. The temperature employed, and operatingconditions, were the same as with the addition of propylene oxide. It is to be noted, however, that ethylene oxide appears to be more reactive and the reaction seems to require a greater amount of cooling water to hold the temperature range, as indicated. .The time required to add the ethylene oxide was about the same, or slightly less, usually just a little more than an hour.

During the addition of the oxides the pressure was held at approximately 50 pounds per square inch gauge pressure, or less. When all the oxide had been added (ethylene oxide being the final addition in'this particular instance) the auto-' clave was permitted to stay at the same temperature range for anotherhalf hour, even longer, if required, or until the gauge pressure had been reduced to zero, or substantially zero, indicating the. reaction was complete. I

The final product was an oily material, somewhat viscous in nature, and having a sort of greenish hue, without any definite odor. It was dispersible in water and soluble in non aqueous solvents, 'such' as aromatic hydrocarbons and others, although not soluble in some non-polar hydrocarbon solvents. The 'final yield was substantially the total weight of the initial reactants. 7

6 Example 2 The same procedure was followed as in Eri ample 1, preceding, except that the order of addition of the oxides was reversed, the ethylene oxide being added first and the propylene oxide last. The time period, temperature range, pressure, etc., were kept the same as in Example 1, preceding.

' imately one liter, up to a"5.-gallon size. amount of para-menthylcyclohexanol employed Example 3 ample 1, except. that a: mixture, to wit, 256.5-

pounds of propylene oxide and ethylene oxide, were added over'a 2-hour period. This mixture of ethylene oxide and propylene oxide was obtained from 136 pounds of propylene oxide and 130.5 pounds of ethylene oxide. In this instance again the time range, temperature, and pressure were kept substantially the same as in Example 1, preceding;

Example 4 The same procedure, as in Example 1, preceding, was conducted on a laboratory scale, employing a small autoclave having a capacity of approx- ,wa's147.6 grams, the amount of propylene oxide employed was 272 grams, and the amount of ethylene oxide employed was 241 grams. ,The amount of caustic soda employed was 2,4 grams.

The operatingv conditions were substantially the cause there is an obvious hazard-in handling a large quantity of material in an autoclave which is not necessarily present in the use of a small vessel. Y

Example 5 L The same procedure was followed as in Example 4, preceding, in every respect, except the variation described in Example 2, preceding, i. e., the ethylene oxide, was added first and the propyleneoxide added last. A v

The same procedure was followed as in Example 4, in every instance, except the modification previously described in Example 3, to wit,

the propylene oxide and the ethylene oxide, were mixed together and added in approximately 15 minutes toone-half hour." In all other respects,

the procedure was identical with that described in Example 4.

The following table includes a series of com-' pounds or cogeneric mixtures which have been selected as exemplifying the .herein included products. Types of hereinnoted compounds or cogeneric mixtures have been produced in three different ways: (a) First adding the propylene oxide and then the ethylene oxide; (1)) first adding the ethylene oxide and then the propylene oxide; and (c) mixing the ethylene oxide and the propylene oxide all together and adding them simultaneously.

The

The data are 5111551511555 in the following table:

11551551555151'1545551 N 1115511155 51155 Ethylene 51555 I v Hinton 95 g 17751111. Weight weight 1 Weight 1 P55555111 Weight Mom Per Cent Wei'ght Mom 1 5101551: ggg Used,-i11 g in Final 'Used in Rmi 1n Final Usedfln Ratio- 111 Fma Glycol Grams (11 551 ranis G1 151 (1101115 (11 51 Ether Ether Ether Ether A 23s 1. 0 15. 0 715 12. 32 45 555 1'4. 43 1 B 23s 1. 0 10. 0 1,19 20. 55 50 952 21. 55 40 2 c. 23s 1. 0 5. 0 2, 520 45. 15 55 910 43. a 40 3 D 23s 1. 0 10.0 1, 071 1s.- 50 1, 071 24. 5s 45 4 E 23s 1. 0 5. 0 2, 382 41. 1 2,- 40 45. 5 45 5 1 238 1.0 5.0 2,145 37,0, 45 2, 350 54.2 50 5 o 23s 1. 0 s. 5 1, 350 23. 42 48. 5 1,205 27.4 43 7 H 23s 1. 0 9. 2 1, 25s 21. 54 4s. 5 1, 00 24. 52 42.2 I. 23,5 1. 0 9. 0 1, 2 1. 52 47. 4 1, 5 2 5. 2 7 43. 5 (1) J. 23s 1. 0 s. 8 1,248 21,. 5 45. 2 1, 21s 27.55 45. 0 K 238 1.0 8,6 1,355 23.55 49.0 1,202 27.9 49:4 G 23s 1. 0 8.5 1, 35 2:1,. 42 4s. 5 1, 205 27. 4 43. 0 1 7 L. 2,238 1. 0 s. 4 1 321 22. 45. 5 1, 275 29. 0 45. 0 (1) M 233 1.0 8.2 1,455 24. 75 49.5 1,230 27.95 42.3 N 23s 1. 0 s. 0 1, 444 24. 4s. 5 1, 295 29. 4 4s. 5 o 23s 1. 0 7. 3 1, 445 24. 47. 4 1, 570 31.1 44. g P. 238 1 0 7. 0 1, 55s 28. 72 49.0 3 496 33. 05 44. 0 Q 238 1.0 5.0 1,955 33.90 49.5 1,755 40.2 44.5 R 238 1.0 20.0 309 5.33 25.0 542 14.5 54.0 5 s. 238 1.0 4.5 1, 541; 25.7 25. 0 4,170 94.7 70.0 9 T. 235 1.0 4. 1 4, 520 77.5 j 75.0 1, 90 27.0 20,0 ,10 U 2, 238 1.0 20. 0 714 12.3 50. 0 258 5.42 20.0 11

1 Within inner m n-guin- 515 1 Duplicated for convenience. 3 Indicates limits of trapezoidal area. In 5115 pr paration of 5115 505 5- 5551 555551115 21) aotostieoi 2 44351146) 55151 alkaline" catalyst 115559755 either flake caustic 30 1 13) RQ'(Q3H5O) 24(Q2H4O)29H soda finely ground 15151 11 01551- and est1e, 0r 1, 3O ,C H Q C H Q powdered sodium methylate, equivalent to' 5 (15} RO (C3H5O)25(C2H4O)30H by weight of the para-menthylcyclohexanol which (16) R ,()(Q H o) '(c I-I40)2 (C3H6Q) 111-1 was employed. I I (l7) RO(C3I I5O)'13(C2l-I4Q)fi'itczHsQhol-l For reasons which are pointed out herein- 39 (13 oma-r 0 11 0) 7(c 150) 1-1 after in greater detail, it is substantially iiri- (1.9) RO (C;H5O')15(C2I I4O)27(CaI-I6Q)sl l possible to use conventional methods and obtain (20') RQtqgHeQl15(C2H4O)27(C3H5O)7H, a single glycol ether of the kind described.- (21 30(CZH40)l4(C3H6Q)23(c2I:LiQ)13H Actually, one Obtains a cogeneric mixture of (22") RQ(C2H Q) 1'5(C3H6 O) 2 (C 5H4Q) 12H closely related or touching homologues. These 40 (Q3) RQ(C2I -I4O 15(C3H5O) 2a(C2l-L1Q)11l-l materials invariably have high molecular weights (24) RO'(C2H4O) 17(-C3H5O)23'(C2H4O) 10H and cannot be separated from one another by any (25) known method without decomposition. The properties of such a mixture represent the contribution of the various individual members of the mixture.

Although one cannot draw a single formula and say that by following such and such 15150551115,

one can obtain 80 or 90% or of such single compound, yet one can readily 5 5 the 151 5155 of a large nuns'be'r of compou ds 5111511 a pear in some of the mixtures described elsewhere, of can be prepared readily as components of mixtures which are manufactured conventionally. Such formulae, representing significant portions of various mixtures, are of distinct value, insofar that they themselves characterize the invention, i. e., describe individual components which are typical of the members of the cogeneric mixture. In the following formulae, since ROE can represent para-rnenthylcy'clohexanol, RO is the ether radical obtained from para-menthyl cy'clohexanol by removal of the hydrogen atom attached to the oxygen atom.

if one selectsany hydroxylated compound and subjects" such compound to oxyalkylation, suchas oxyethylation or oxypropylation, it becomes obvious that one is really producing a polymer of the alkylene oxide, except for the termi rial group.- This is particularly true where the amount of oxide addedis comparatively large, for instance, 10,20,30, 40, or 50 units. If such-a compound is subjected to oxyethylat-ion so as to introduce 30 units of ethylene oxide, it iswell known that one does notobtain' asingle constit= uent, which, for the sake of convenience, may be indicated as R '(C;2H4O)'30H; Instead; one ob tains a cogeneric mixture of closely related-homo logues-, in which the formula may be sho'wn as the following; RO(CzH4O)nI-I, wherein n, as far 9 as the statistical average goes, is 30, but the individual members present in significant amount may vary from instances where n has a value of 25, and perhaps less, to a point where-n may represent 35 or-more. Such mixture is, as stated, a cogeneri'c, closely related series of touching homologous compounds. Considerable investigation has been made in regard tothe distribution curves for linear polymers. Attention is directed to the article-entitled fFundamental Principles of Condensation Polymerization, by

Paul J.-:Flory, which appeared inChemical Reviews, volume 39, No. 1, page 137.

Unfortunately, as has been pointed out by Flor-y and'other investigators, there is nosatisfactory method, based on either experimental or mathematical examination, of indicating the exact proportionof the various membersof touching homologous series which. appear in cogeneric condensation'products of the kind described. This means that fro'm' the' practical standpoint, i.-- e.; the ability to describe" how to make the product under consideration, and how to-repeat such production time after time without diificulty, it is necessary to resort to some'other method of description.

Actually, from a' practical standpoint, it is much more satisfactory, perhaps, to describe the ultimate composition in terms of the reactants, i. e., menthylcyclohexanol and .the two alkylene oxides. The reasonfor this statement is the following: If oneselects a specific compound, it must be borne in mind that such compound is specific only insofar that the cogeneric mixture, in terms of a statistical average, will conformto thisformula. Thismay be illustrated by an example, such as RO(C3H60) 2'3(C2H40)27H; If one inbines the reactants in the predetermined weight ratio so as togive theoretically this specific component, and assuming. only one chemical compound were formed, what happens is :that, although this particular compound may be present in asignificant amount, and probably less than 50%, actually, one obtains a cogeneric mixture of :ztou'ching 'homo'logues, in which the statistical average does correspond to this formula. For instance, selecting reactants, which, at least theoretically, could give the single compound R.Q(C3H60) 23 (C2H4O)2'1H, what actually happens is that one obtains a sort of double cogeneric mixture, for the reason that in each batch or continuousaddition of alkylene oxide, a cogeneric mixture is formed. Since the present products require the addition of at least two diiferent multimolar proportions of each of two different alkylene oxides (ethylene oxide and propylene oxide), it becomes obvious that a rather complex cogeneric mixture must result.

This can be' best illustrated by example. Assume that one isggoingto use theindicated ratio,- to wit, one pound of menthylcyclohexanol, 23 pounds of propylene oxide and 27 pounds of ethylene oxide. The initial step involves the treatment of one pound mole of menthylcyclohexanol with 23 pound moles of propylene oxide, so as to yield theoretically RO(C3H60)23H;- actually, as pointed out, one does not obtain in which n is 23, but one obtains a cogeneric mixture in which there are present significant amounts of homologues, in which n varies from 10, ll and 12 on up to 35, 36 and possibly 40 or beyond. A statistical average, however, must, of course, correspond to the proportion of'the initial reactants, i. e., a compound of the formula RO(C8H60)23H, which is present undoubtedly to a significant extent;

When this 'cogeneric mixture is then subjected to reaction with 27 moles -of ethylene oxide, it becomes obvious that, although one may obtain some RO(C3H6O)23(C2H4O)27H, yet this particular product can only be present to a'minorextent, for reasons which have been described in connection with oxyethylation and which now are magnified to a greater degree by oxypropylation. -Stated another way, it is probable that the cogener-ic mixture represents something like RO(C3H60)1L(C2H40)1L'H, in which, as previously pointed out,- components present in important percentages are those in which n could vary anywhere from 10 or higher, up to or 40. By the same-token, components present in important percentages are those in which n could-vary anywhere from 13 or 1%, and possibly even less, up to 10, 41, 42, 43 or 45. Indeed, homologues of a lower or ahighervalue of n'and-n will be present in minor amounts, the percentages of-- such components decreasing, the further removed-they are from the average composition. However,-in spite of such variation in regard to the cogeneric mixture, the ultimate composition, based onthe ingredients which enter into it and based on the statistical average of such constituentscan still be expressed by the formula RO (CaHeO) 23 (C2H4O) 27H then the constituents are added in actual molar proportions, based on whole numbers. IL-how ever, one selects a point in the inner triangular area, which, when recalculated in terms of molar proportions, produces a fractional number, there is still no reason why such proportion of initial reactant should not be adopted. For instance,

H one might select a point in the triangular graph,

which, when calculated in terms of molecular proportions, represents a formula, such as the following: RO(C3H6O)23.5(C2H4O)27H; This, of course, would be immaterial, for the reason that if one starts with a pound mole of menthylcyclohexanol and adds 23.5 pound moles of propylene oxide, one will obtain, on the average, a mixture closely comparable to the one previously ,described, using exactly 23 pound moles of propylene oxide instead of 23.5. Such mixture corresponds to the compound RO(C3H60)23.5H only'in' the sense of the average statistical value, but not in the sense that there actually can be a compound corresponding to such formula. 7 Further discussion of this factor appears unnecessaryjn light of what has been said previously.

Such mixture could, of course, be treated with 2'7 pound moles of ethylene oxide. Actually, all

that has been said sums up to this, and that is, that the mostrsatisfaetory way, a s has been said before, of indicating actual materials obtained by the, usual and conventional oxyalkylation. process, is interms of the initial reactants, and it is obvious that any particular point on the tri n angular graph, from a practical aspect, invariably and inevitably represents the statistical average of several or possible a dozen or more closely related cogeners of almost the same. composition, but representing a series of touching homologues. The particular point selected represents at least the composition of the mixture expressed empirically in the terms of. a compound. representing the statistical average.

Previous reference has been made to the fact that comparatively few oxyalkylated derivatives of simple hydroxylated compounds find utility in actual demulsification practice. We have pointed out that we have found a very few exceptions to this rule. The fact that exceptions exist, as in the instant invention, is still exceedingly difficult to explain, if one examines the slight contribution that the end group, derived from the hydroxylated material, makes to the entire compound. Referring for the moment to a product of the kind which has been described and identified by the formula RO(C3H60)23(C2H40)27H, it becomes apparent that the molecular weight is in the neighborhood of 2900, and actually, the paramenthylcyclohexanol contributes less than 10% of the molecular weight. As a matter of fact, in other comparable compounds the para-menthylcyclohexanol may contribute as little as 4% or 5% and yet these particular compounds are effective demulsifiers. Under such circumstances, it would seem reasonable to expect that some other, or almost any other, substituted cyclic 6- carbon atom compound comparable to paramenthylcyclohexanol, would yield derivatives equally efiective. Actually, this is not the case. We know of no theory or explanation to suggest this highly specific nature or action of the compound. or cogeneric mixture derived from paramenthylcyclohexanol.

Referring to an examination of the previous list of 32 compounds, it is to be noted that in certain examples, for instance, Examples 9 to 15, inclusive, all the propylene oxide is added first and then the ethylene oxide is added. Compounds indicated by Examples 1 to 8 are substantially A the same as far as composition goes, but are reversed, insofar that the ethylene oxide is added first and then the propylene oxide. Other compounds having substantially the same ultimate composition, or at least, very closely related ultimate compositions, having a further variation in the distribution of the propylene oxide and ethylene oxide, are exemplified by Formulae 16 to 32, inclusive.

As has been pointed out previously, for some reason which we dot not understand, and for which we have not been able to offer any satisfactory theory, we have found that the best compounds, or, more properly, cogeneric mixtures, are obtained when all the propylene oxide is added first and then all the ethylene oxide is added. Although this is true to at least some extent in regard to all compositions within the trapezoidal area in the triangular graph, yet it is particularly true if the composition comes within the segment of the circle previousl referred to in the drawing. In such event, one obtains a much more effective demulsifier than by any other combination employing ethylene oxide alone, propylene oxide alone, or any variation in the mixture of the two, as illustrated by other formulae. In fact, the compound, or cogeneric m1xture so obtained, as far as demulsification is concerned, is not infrequently at least one-third better than any other derivative obtained in the 12 manner described involving any of the other above variations.

The significance of what has been said previously, becomes more emphatic when one realizes that, in essence, we have found that one isomer is a more effective demulsifying agent than another isomer. The Word isomer is not exactly right, although it is descriptive for the purpose intended insofar that we are not concerned with a single compound, but with a cogeneric mixture, which, in its statistical average, corresponds to such compound. Stated another way, if we start with one. pound mole of menthylcyclohexanol, 23 pound moles of propylene oxide and 27 pound moles of ethylene oxide, we can prepare two different cogeneric mixtures, which, on a statisical average, correspond to the following: RO C2H4O 25C3H5O)21H and RO(C3H6)23(C2H4O)27H. There is nothing we know which would. suggest that the latter be a much more efiective demulsifying agent than the former, and also that it be more effective for other industrial purposes. The applicants have had wide experience with a wide variety of surface-active agents, but they are unaware of any other similar situation, with the exception of afew instances, which are the subject-matter of other copending applications, or under investigation. This feature represents the invention within an invention previously referred to, and, thus, becomes the specific subject-matter claimed in our co-pending applications Serial Nos. 124,813 and 124,814, both filed November 1, 1949.

Reference has, been made to the fact that the product herein specified, and particularly for use as a demulsifier, represents a cogeneric mixture of closely related homologues. This does not mean that one could not use combinations of such cogeneric mixtures. For instance, in the previous table, data have been given for preparation. of cogeneric mixtures which statistically correspond, respectively, to points I', 3 and 6. Such three cogeneric mixtures could be combined in equal weights so as to give a combination in which the mixed statistical average would correspond closely to point 1. 1

We need not add that instead of subjecting menthylcyclohexanol alone to oxyethylation, and oxypropylation, or inversely, oxypropylation and oxyethylation, or a simultaneous treatment of both oxides, one can emplo a mixture of menthylcyclohexanol, along with some other desired reactant, such as alpha-'terpineol. For a number of reasons, it is ordinarily desirable to use procedure in which only one product is reacted at a time.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid. oil, cresol', anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of our process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other 13 suitable well-known classes; of demulsifying agents.

It is well known that conventional demulsify ing agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oiland water-solubility. Sometimes they may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of 1 to 10,000, or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000, as in desalting-practice, such an apparent insolubility in oil and Water is not significant, because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

In practising our process for resolving petroleum emulsions of the Water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatus now generally used to resolve or break petroleum emulsions: with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of precedure. is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type of demulsification procedure to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for

example by agitating the tank of emulsionand slowly-dripping demulsifier into the emulsion. In some cases mixing is achieved by heating the emulsion whiledripping in the demulsifier, depending upon the convection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a

.circulatingpump withdraws emulsion from, e. g.,

the bottom of the tank, and i e-introduces it into the top of the tank, the demulsifier bein added, for example, at the suction side ofsaid circulatin ump.

In .a second type of treating procedure, the demulsifier is introduced into the well fluids at the well-head or at some point between thewelL head and the final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarilythe flow of fluids through the subsequent lines and fittings suflices .to produce the desired degree of mixing of demulsifier and emulsion, although in some .instances additional mixing devices may be introduced into the'flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent settling of the .chemicalized emulsion. Heating devices may likewise be incorporatedin any of the treating proceduresdescribed herein.

A third type of application (do'wn-the-hole) of demulsifier; to emulsion is to introduce the demulsifier either periodically or continuously in dilutedor undiluted form into the well and to allow it to come to the surface with the well fluids, and then 'to flow the chemicalized emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of application is decidedly useful when the demulsifier is used in connection wtih acidification of calcareous oil-bearingstrata, especially if suspended in or fldissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, the broad process consists simply in introducing a relatively small. proportion of demulsifier into a relatively large propotion of emulsion, admixing the chemical and emulsion either through natural flow or through special apparatus, with or without the aplication of heat, and allowing the'inixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the mass;

The following is a typical installation:

A reservoir to hold the demulsifier of the kind described (diluted or undiluted) is placed at the well-head where the effluent liquids 'leave the well. This reservoir or container, whichimay vary from-5 gallons to 50 gallons for'convenience, is connected to a proportioning pump whichinject the demulsifier drop-wise into the fluids leaving the well. Such' chemicalized fluids pass through the flowline 'intoa settling tank; The settling tank consists of a tank of any convenient size, for instance, orle which will hold amounts of fluid produced in 4 to 24 hours (500 barrels to 2000 barrels capacity), and in which there is a perpendicular conduit fromthe top of the tank to almost the very bottom so as to permit the incoming fluids to pass from the top of the settling tank to the bottom, so that such incoming fluids do not disturb Stratification which takes place during the, course of demulsification. The settling tank has two outlets, one being below the water level to drain off the water resulting from demulsification or accompanying the emulsion as free water, the other being an oil outlet at the top to permit the passage of dehydrated oil to a second tank, being a storage tank, which holds pipeline or dehydrated oil. If

desired, the conduit or pipe which serves to carry I the fluids from the well to the settling tankmay include a section of ipe with baflies to serve as a mixer, to insure thorough distribution of the demulsifier throughout the fluids, or a heater for raising the temperature of the fluids to some convenient temperature, for instance, to F., or both heater and mixer.

Demulsification procedure is started by simply setting the pump so as to feed a comparatively large ratio of demulsifier, ro'rinstance, 125.000. As soon as a complete break or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being added is just suflicient to produce clean or dehydrated oil. The amount beingfed at such stage is usually 10,000, 1:15,000, 1:20,000, or the like. In'many instances the'oxyalkylated products herein specified as demulsifiers can be conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing '75 parts by weight of an oxyalkylated derivative, for example, the product of Example 1, with 5 parts by weight of xylene and 10 parts by weight of isopropyl alcohol, an excellentv demulsifieris obtained. Selection of the solvent will vary, depending upon the solubility characteristics of the oxyalkylated product, and of course, will be dictated in part by economic considerations, i. e., cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical demulsifier. For example, a, mixture which 'exemplifies such combination is illustrated by the following I Oxyalkylated derivative, for product of Example 1, 20%;

A cyclohexylamine salt of a polypropylated naphthalene monosulfonic acid, 24%;

An ammonium salt of a polypropylated naphthalene monosulionic acid, 24%;

-A sodium salt of oil-soluble mahogany petroleum sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent, 5%;

Isopropyl alcohol, 5%.

The above proportions are all weight percents.

Throughout the specification elsewhere reference has been made to homologues. It is'quite likely that it would be equally proper, in numerous instances, andperhaps all the herein described products, to refer to isomers, as well as homologues. The reason for this statement is that propylene oxide, as differentiated from ethylene oxide, can, at least theoretically, combine with a hydroxylated material ROI-I to give two difierent derivatives, one being a primar alcohol and the other a secondary alcohol. This is illustrated by the following.

example, the

0 Elsewhere in the specification the word isomer has been used thus: isomer.- It is not believed there is any confusion between such terminology in that particular instance, and what issaid immediately preceding.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking petroleum emulsions menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide and, propylene oxide in such weightv proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoidal area defined approximatel in the accompanying drawin by points 8, 9, i0 and H.

2. A. process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including acogeneric mixture ofa homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition ofsaid cogeneric mixture stated in terms of initial reactants lies approximately within the trapezoidal area defined approximately in the accompanying drawing by points 8,9, I0 and I I.

3. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived 6X- clusively from para-menthylcyclohexanol, ethylene oxide and propylenev oxide in such weight proportions so the average composition of said c0 generic mixture stated in terms of initial reactants lies approximately within the segment of the circle in the accompanying drawing in which the minimum para-menthylcyclohexanol content isv at least 4% and which circle is identified by the fact that points I, 3 and 6 lie on its circumstance.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively' from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such Weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the triangular area defined in the accompanying drawing by points I, 3 and 6.

5'. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture-being derived exclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the triangular area defined in the accompanying drawing by points 2, 4 and 5.

'6. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture bein derived e'xclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately at point 7 in the accompanying drawing.

7. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier includin a single cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately at point 1 in the accompanying drawing.

MELVIN DE GROOTE.

ARTHUR F. WIR'I'EL.

OWEN H. PETTINGILL.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 2,130,525 Coleman et al Sept. 20, 1938 2,176,834 Bruson Oct. 17, 1939 2,213,477 Steindorfi et a1 Sept. 3, 19.40 2,233,383 De Groote et a1 Feb. 25, 1941 2,243,330 De Groote et al May 27, 1941 2,307,058 Moeller Jan. 5,1943 2,317,726 Boedeker et a1 Apr. 27, 1943 2,330,474 De Groote Sept. 28, 1943 2,425,755 Roberts et a1. Aug. 19, 1947 2,425,845 Toussaint et al. Aug. 19, 1947 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE, CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFER INCLUDING AT LEAST ONE COGENERIC MIXTURE OF A HOMOLOGOUS SERIES OF GLYCOL ETHERS OF PARAMENTHYLCYCLOHEXANOL; SAID COAGENERIC MIXTURE BEING DERIVED EXCLUSIVELY FROM PARA-MENTHYLCYCLO- 